"Wine" with reduced alcohol concentration, typically of around 50% of the usual alcohol concentration, e.g., about 6% volume/volume, is a product for which a demand now exists as of the date hereof. Ideally, the low alcohol wine should possess all normal properties of the wine, including taste and bouquet, except for properties related directly to the alcohol concentration, e.g., mouth-feel.
For the sake of brevity in the following, such a fermentation product will be identified as a low alcohol wine or light wine, even though some countries, e.g., Switzerland, defines wine as a fermented product from grape juice containing not less than 8% alcohol. Also in the following, all percentages given are on a volume/volume basis, unless otherwise indicated.
Several methods have been suggested to the art to produce a low alcohol wine. However, insofar as the inventor hereof is aware, each of the various methods known to him suffer from one or more significant disadvantages.
Some of the methods treat the wine. Thus, wine of normal alcoholic content may be distilled to obtain a bottoms product with the desired low alcohol concentration. However, several volatile constituents, including low boiling aroma substances, become removed from the finished low alcoholic wine. Also, the product exhibits an unwanted "boiled" taste. Finally, the method is relatively expensive, notwithstanding that an alcohol co-product results. A suggestion has been posed by U.S. Pat. No. 4,468,407 to freeze a standard wine, then separate the frozen (alcohol poor) fraction and the liquid (alcohol rich) fraction, followed by thawing the frozen fraction and combining the thawed liquid with a standard wine. This method, however, is highly energy-consuming and also, some of the aroma substance are lost in the alcohol rich fraction.
Another method for production of a low alcoholic wine employs osmosis. Also in this method, aroma constituents are lost, notably low molecular weight aroma constituents, and also, this method is expensive.
Still another method for production of a low alcoholic wine compises dilution of normal wine with water. This approach, however, is illegal in some countries, and, moreover, the low alcoholic wine exhibits a somewhat unpleasant "diluted" taste. Of course, fruit juice may be employed as the diluent, but this changes the taste.
Some methods propose changes in wine making procedures. Thus, one method compises harvesting the grapes at a time when the sugar content of the grapes is still low, whereafter, wine is produced in the normal way. However, the aroma development and the typicity of the grapes are not then fully developed. Thus, the quality of the finished low alcoholic wine is inferior, and disadvantageously this method requires change in the harvesting time.
Another method comprises fermentation of grape juice with yeast in the conventional manner only until around 50% of the sugar is fermented, whereafter the fermentation is stopped by cooling, whereupon the alcohol (and aroma constituents) are removed by evaporation. Then, fermentation is initiated in the alcohol-free liquid, and the process is completed as a usual wine fermentation. The finished low alcoholic wine, however, contains only around half of the normal aroma constituents, and also, the method is expensive due to the cooling and the evaporation.
Still another method comprises removal of the yeast well before the end of the fermentation, e.g., by centrifugation or sterile filtration. This method, however, is not attractive as the residual sugar content generates a wine with an unwanted sweet taste.
As appears from the above, none of the prior art methods for production of low alcoholic wine are completely satisfactory. On the whole, removing alcohol from normal alcohol content wine or altering the usual mechanics of wine making methods to reduce alcohol content detrimentally affect and/or aroma.
The object of this invention is to provide a method for reducing the alcohol content in wines, yet retaining all normal wine properties except, of course, mouth feel properties related directly to the alcohol concentration.